So-called ink-jet recording has come to be used practically in which droplets of a recording liquid containing a water-soluble dye, such as a direct dye, an acid dye, etc., and a solvent are ejected through a minute nozzle orifice to construct images on a surface of a recording material.
Solvents that can be used in a recording liquid for ink-jet recording are severely restricted. That is, the solvents are required to give a durable recording liquid which can rapidly deposit to adhere to general-purpose recording papers for business and office use, such as paper for use in electrophotographic copiers and other PPCs (plain-paper copiers) and fanfold paper (continuous paper for use in computers etc. and to give high-quality printed characters, i.e., printed characters sharply outlined and non-blotting.
Dyes for use in a recording liquid for ink-jet recording, on the other hand, are required to have sufficient solubility in suitable solvents that are restricted in kind as described above, to be stable over a prolonged period of storage, and to give printed images having high densities and excellent water resistance, light resistance, and ozone resistance. However, it has been difficult for a dye to meet all these requirements simultaneously. In particular, since excellent light and ozone resistance has been attained with organic or inorganic pigments used as colorants in other printing techniques such as, for example, electrophotographic printing and thermal melting and transfer printing, there has been a strong desire for development of a recording liquid containing a dye having excellent light and ozone resistance comparable to that of the above organic or inorganic pigments. Although various proposals for the above purpose have been made in, for example, JP-A-55-144065, JP-A-57-30773, JP-A-57-207660, JP-A-58-147470, JP-A-62-190269, JP-A-62-190271, JP-A-62 190272, and JP-A-62-250082 (the term "JP-A" as used herein means an "unexamined published Japanese patent application"), these proposals are still insufficient in meeting the demand of the market.